The present inventive concept relates to a nonvolatile memory device and a method for testing a nonvolatile memory device using a variable resistance material.
Nonvolatile memory devices using a resistance material may include a phase change random access memory (PRAM), a resistive RAM (RRAM), a magnetic RAM (MRAM), and the like. A dynamic RAM (DRAM) or a flash memory device stores data using charges, whereas a nonvolatile memory device using the resistance material stores data using the state change of a phase change material such as a chalcogenide alloy (in the case of a PRAM), a resistance change of a variable resistance material (in the case of an RRAM), a resistance change of a magnetic tunnel junction (MTJ) thin film according to a magnetization state of a ferromagnetic material (in the case of an MRAM), and the like.
Here, a phase change memory cell will be described as an example. A state of a phase change material is changed to a crystal state or an amorphous state while the phase change material is cooled after being heated. The phase change material in a crystal state has relatively low resistance, and the phase change material in an amorphous state has a relatively high resistance. Accordingly, memory cells where the phase change material is in the crystal state may be defined as storing set data (e.g., logic “1”), and memory cells where the phase change material is in the amorphous state may be defined as storing reset data (e.g., logic “0”).